[clang] [C++20] [Modules] Introduce -fgen-reduced-bmi (PR #85050)

[Iain Sandoe via cfe-commits]

https://github.com/iains commented:


I have no issue with the general intention or phasing here; my main concern is that we are introducing [yet] another user-facing modules option that actually we intend will become irrelevant after a few releases.

In practice, removing user-facing options is not very easy.

So:
  1. Perhaps we could have only the cc1 option and you could introduce some temporary handling in the driver to recognise it and amend the --precompile behaviour?
  2. Maybe the project could introduce something like -fexperimental-xxxx-xxxx with a clear statement that fexperimental flags cannot be relied on to be stable (or even present) in any future release)?

https://github.com/llvm/llvm-project/pull/85050